The immediately preceeding parody (which claims to date from a coffee shop in 1962) seems to have a similar basis to the one I quoted above, which was certainly in print by 1970 (also anon.)
However, that coffee shop claim may be spurious as the mention of Vietnam makes the date appear questionable.
"Nov 14-16 1965: First major military engagement between U.S. & N.Vietnam troops" (from This site.)
It seem that 1962 is to early to consider Vietnam a 'topical' reference.
Anyone with further details ?

Nigel